1. Field of Invention
The present invention relates to an antenna. More particularly, the present invention relates to a slot and multi-inverted-F coupling wideband antenna and an electronic device thereof.
2. Description of Related Art
In keeping pace with progress in telecommunication technology, application of the telecommunication technology for hi-tech products has been increasing and related telecommunication products have become diversified. In recent years, the consumer functional requirements for telecommunication products have become increasingly higher; therefore, telecommunication products with various designs and functions are continuously brought to market, such as the design consolidation of telecommunication products with dual-band and triple-band, the computer network products with wireless networks are in demand. In addition, due to the maturity of integrated circuit technologies, the trend for products is leading towards lighter, thinner, and smaller.
In telecommunication products, the main function of an antennas is for transmitting and receiving signals. Today, as the trend for products is towards lighter, thinner, and smaller, the inverted-F antennas have become more popular in the market. FIG. 1 is a structural schematic diagram of a conventional inverted-F antenna. The antenna mainly includes a radiator 101, a ground plate 102, and a signal source 103. In addition, an antenna length 104 is also shown in FIG. 1. Because the radiator 101 and the signal source 103 form a shape of an inverted F, it is called an inverted-F antenna. The aforementioned type of antenna mainly makes use of the principle of current excitation.
In addition, Hon Hai Precision Industry Co. Ltd has presented a dual frequency antenna under a U.S. Pat. No. 6,812,892. FIG. 2 is a structural schematic diagram of a conventional dual frequency inverted-F antenna under the U.S. Pat. No. 6,812,892. The antenna includes two inverted-F antennas, which are illustrated in FIG. 2 as the first inverted-F antenna 201 and the second inverted-F antenna 202. Two radiators 204 and 205 are extended from the tail end of the original inverted-F antenna, so that a dual inverted-F antenna is formed. In which, the shorter antenna 202 is used for receiving higher frequency signals such as 5.2 GHz signals under radio communication protocol 802.11a while the longer antenna 201 is used for receiving lower frequency signals such as 2.45 GHz signals under radio communication protocol 802.11b.
FIG. 3 is the voltage standing wave ratio (VSWR) diagram of the aforementioned conventional antenna in FIG. 2. As can be determined from FIG. 3, the lower range operating frequency of the antenna is around 2.45 GHz while the higher range operating frequency is around 5 GHz to 6 GHz. However, based on modern applications, for example, the Worldwide Interoperability for Microwave Access (WIMAX) brought forward by Intel Co. requires a bandwidth between 2.3 GHz to 2.5 GHz. The antenna in FIG. 2 cannot provide such a large bandwidth.